IMVHO lockdowns have no sanitary reasons, they simply haven't enough prime matters and/or energy and/or food so they need to force a big stop without telling the real reason to a population used to grow year on year and work hard any day...

Witch is not much different than lowering down speed limits or asking to lower head/air-con usage in various EU countries.

Not much time ago VoxEU publish https://voxeu.org/article/trade-and-travel-time-epidemics a reasoning about how travels can be limited without hurting the economy and there are many other in the same line of thought. Honestly I see no other explanation.